Wien filter with integrated vacuum pump

Abstract

An integral Wien filter and vacuum pump for separating charged particles or for orienting their spin direction while maintaining optimal beamline vacuum. The vacuum pump is an ion pump including one or more cylindrical Penning cells to trap and expel electrons. The Wien filter includes orthogonal electric and magnetic fields to direct particles with the desired speed through the device while deflecting particles at undesired speeds. The Wien filter includes two electrodes, one biased positive and one biased negative, a dipole magnet, and means for reversing polarity of the electrodes to flip the spin of the charged particles. Metal plates on either side of the Penning cells embed gas that is ionized by trapped electrons in the Penning cell thus creating vacuum by turning gas into solid. The two metal plates can be configured to obtain vacuum pumping via chemical gettering and for removal of noble gases.

What is claimed is: 
     
       1. A filter with integrated vacuum pump, comprising:
 a Wien filter to orient the spin direction of a polarized electron beam; 
 an ion pump including a pair of electrodes, said electrodes including one or more cylindrical Penning cells to trap and expel electrons; 
 a means to apply a magnetic field parallel to the axes of each of the Penning cells to trap and expel electrons trapped in the Penning cells; 
 a means to apply an electric field to the Wien filter; and 
 metal plates on opposing sides of the Penning cells, the metal plates to embed gas ionized by trapped electrons in the Penning cells and create vacuum by turning gas into solid. 
 
     
     
       2. The filter with integrated vacuum pump of  claim 1 , comprising at least one of said metal plates is constructed of titanium to provide vacuum pumping via chemical gettering. 
     
     
       3. The filter with integrated vacuum pump of  claim 2 , comprising a second of said metal plates is a material selected from the group consisting of titanium and tantalum. 
     
     
       4. The filter with integrated vacuum pump of  claim 1 , comprising:
 a first of said metal plates is constructed of titanium to provide additional vacuum pumping via chemical gettering; and 
 a second of said metal plates is constructed of tantalum to provide pumping of noble gases. 
 
     
     
       5. The filter with integrated vacuum pump of  claim 1 , wherein the Penning cells comprise a pump speed of at least 30 liters/second. 
     
     
       6. The filter with integrated vacuum pump of  claim 1 , wherein the Penning cells provide optimized pumping when biased with positive voltage from 3 to 10 kV.